Thread: Discovery 2 TD5 Torque Converter Mods

hi guys
just a quick question on the lock up of the converter my td5 doesn't lock up til 85km/h is this unusual has now done 200,000kms and done some heavy towing could box or converter be getting a bit long in the tooth ? still changes nice any thoughts

thanks mark

Originally Posted by markd2

hi guys
just a quick question on the lock up of the converter my td5 doesn't lock up til 85km/h is this unusual has now done 200,000kms and done some heavy towing could box or converter be getting a bit long in the tooth ? still changes nice any thoughts

thanks mark

80km/h for a D2 is normal for lockup in 4th. Sounds fine to me.

is that 85 KPH indicated or 85 Kph real... (check it with a GPS)

whats on the speedo can be faster than your acutally going.

but even then Id call 5K over acceptable (at least partially cause ID want the auto to leave the workshop so I didnt have to touch it )

The lockup can be anywhere from just under 80km/h up depending on how its being driven. Tyres etc wont make much difference to the minimum lockup speed, it's whatever the speedo is displaying. The speed is determined by the ABS sensors, nothing mechanical like transfer case drives etc.

Higher (than V8 petrol) stall speeds through the torque convertor on "Turbo'd" diesel engines is to allow the engine and Turbo revs to be higher at take off, which allows the Turbo to Spool up and reduce Turbo Lag, simply speaking, Regards Frank.

Yes Frank I thought along those lines but 2800rpm is a bit over the top. I think this motor would have enough boost and plenty of torque by the time it reached 2200rpm.

thanks guys

speed is with gps just didn't know if 85kms was high thanks again all for the info

cheers mark

In my DII transmission lockup happens at around 80 Km/Hr in both 3rd and 4th gear. This is the mechanical lockup which turns the Torque converter into a direct drive..
As for torque converter stall speeds .. my reading of this ( as a lifetime manual driver in the process of selling an Auto TD5 which I have replaced with a manual ) is that it is the speed at which the torque converter stops being a torque multiplier with the input and output turning at different speeds to become a more or less 1:1 fluid drive. This speed depends on the input torque and the load.. so upgrading the engine and its torque will cause the TC to slip to higher speeds and raise the "stall speed" so a heavier TC would be appropriate. As for changing the TC on a standard engine.... there must be a good reason and I suspect a lot of R&D that has gone into the selection that LR ( BMW ) used in these rigs.. It is possible of course that it was designed for different market expectations than ours - the USA for instance.
What would be more useful would be manual control of the TC lockup function so that we could pull in direct drive from say 2000 RPM in all gears rather than waiting for 80 KM.... but then it would be simpler and more efficient to get a manual with the extra gear and full control.

Trevor